<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .noe{
            width: 800px;
            height: 400px;
            background-color: cadetblue;
            display: flex;
            justify-content: space-between;
        }
        .noe1{
            width: 200px;
            height: 400px;
            background-color: chocolate;
            text-align: center;
            line-height: 400px;
        }
        /* 屏幕缩小到600px以下时,第一个盒子隐藏 */
        @media (max-width:600px) {
            .noe .noe1:nth-child(1){
                display: none;
            }
            
        }
    </style>
</head>
<body>
    <div class="noe">
        <div class="noe1">1</div>
        <div class="noe1">2</div>
        <div class="noe1">3</div>
    </div>
</body>
</html>